Electric energy storage may be provided by secondary batteries, such like lithium-ion batteries. Such batteries but nearly all kind of secondary batteries should be operated within a predefined temperature range. For instance, at very low temperature, e.g. lower than −10° C., battery performance declines and efficiency may drop remarkably. At higher operating temperatures, e.g. around 40° C. and above, the economic life-time as well as performance and capacity of such batteries typically reduces.
These thermal conditions require that such batteries and battery modules have either to be heated or cooled appropriately. Consequently, there is a need for an adequate thermal management for batteries.
Electrochemical cell shapes are generally classified as either prismatic or cylindrical. Cylindrical cells have cylindrical housings. Prismatic cells have prismatic housing shapes, such as parallelepipeds. Common examples of prismatic cells include standard 12 V car batteries. An electrochemical cell can be, for example, a lithium ion cell.
Lithium-ion batteries are often packaged in so-called “pouch cells”. An advantage of pouch cells is that the traditional metallic cylinder and glass to metal electrical feed-through is replaced by a relatively inexpensive foil packaging similar to what is used in the food industry. The foil is often a lamination film made from aluminum. The electrical contacts generally consist of conductive tabs that are welded to the electrode and sealed in the pouch material.
Document WO 2010/071463 A1 describes electrochemical cells placed inside a housing which are in thermal contact with a Peltier cell. The Peltier cell provides heat transfer into or out of a cell pack, whereas thermal-conducting separating plates in contact with at least one sidewall are placed inside said housing with the electrochemical cells placed between the plates. There, a sidewall of the housing is in contact with said separating plates and is further in thermal contact with the Peltier cell.
Moreover, the separating plates sandwiched between electrochemical cells have back edges bent at an angle of 90° contacting with the sidewall. Those back edges are further riverted together with said sidewall.
Since the separating plates protrude from lateral edges of the electrochemical cells, the cells have to be positioned and assembled at a particular distance from the sidewall of the housing. As a consequence, the interior space of the housing cannot be completely filled with electrochemical cells.
It is therefore an object of the present invention to provide a space-optimized housing for an electric battery, which provides improved thermal management. It is a further aim to optimize size and weight of a secondary battery together with an efficient cooling or thermal management of the battery.